The addition of alkali metal salts or alkaline earth metal salts of inorganic or organic acids (see, for example, DE-OS [German Published Specification] No. 1,930,257 (LeA 12,278) or DE-OS [German Published Specification] No. 2,149,311 (LeA 13,999)), if appropriate in combination with halogen compounds and glass fibers (see, for example, DE-OS [German Published Specification] No. 2,148,598 (LeA 13,970)), is known.
The addition of halogenated, low molecular weight aromatic polycarbonates and if appropriate inorganic or organic antimony compounds to thermoplastic resins, for example, thermoplastic polycarbonates (see DE-OS [German Published Specification] No. 2,243,226) is also known.
The use of halogenated phthalimides with the stated alkali metal salts and if appropriate perfluoroethylene (see DE-OS [German Published Specification] No. 2,703,710 (LeA 17,759) and U.S. Pat. No. 4,208,489) is also known.
Japanese Patent Publication No. 75-64337 also discloses that thermoplastic resins, for example, aromatic polycarbonates, may be provided with halogenated phthalimides and if appropriate other flameproofing auxiliaries, such as Sb.sub.2 O.sub.3.
Japanese Patent Publication No. 75119401 also discloses that thermoplastic resins, for example, aromatic polycarbonates, may be provided with halogenated phthalimides and if appropriate, other flameproofing auxiliaries, such as Sb.sub.2 O.sub.3, and if appropriate further additives, such as, for example, glass fibers.
Polycarbonates with a content of organic alkali metal salts and/or alkaline earth metal salts, characterized in that they contain an inorganic alkali metal halide or alkaline earth metal halide and/or an organic aromatic or heterocyclic halide, are also known. If appropriate, siloxanes, fluorinated polyolefins or glass fibers can also be added. However, tetrahalogenophthalimides are not included as organic halides (see DE-OS [German Published Specification] No. 2,744,016 together with U.S. patent specification No. 3,919,167).
Finally, mixtures of polycarbonates, organic halogen compounds, alkali metal salts or alkaline earth metal salts and substances which reduce the tendency of polycarbonates to drip (see DE-OS [German Published Specification] No. 2,918,882 and DE-OS [German Published Specification] No. 2,918,883) are also known.
Both halogenated phthalimides and the special bromine compounds can be employed as organic halogen compounds. However, it is not mentioned that the combinations, to be employed according to the invention, of halogen-containing polycarbonates or mixtures of polycarbonates with halogen-containing additives, halogenated phthalimides and alkali metal salts or alkaline earth metal salts of an organic acid have a synergistic effect in respect to the flame resistance of the molding composition.
Neither the combination salt, phthalimide and if appropriate glass fibers, nor the combination salt, special bromine compounds and if appropriate glass fibers stabilize the thermoplastic polycarbonates to such an extent that they do not tend to drip, even under extreme fire conditions.